class_docstr: A Sum of Matrix Expressions
  
  MatAdd inherits from and operates like SymPy Add
  
  Examples
  ========
  
  >>> from sympy import MatAdd, MatrixSymbol
  >>> A = MatrixSymbol('A', 5, 5)
  >>> B = MatrixSymbol('B', 5, 5)
  >>> C = MatrixSymbol('C', 5, 5)
  >>> MatAdd(A, B, C)
  A + B + C
code: def _eval_trace(self):
      from .trace import trace
  
      return Add(*[trace(arg) for arg in self.args]).doit()
  
imports: from functools import reduce
  import operator
  from sympy.core import Basic, sympify
  from sympy.core.add import add, Add, _could_extract_minus_sign
  from sympy.core.sorting import default_sort_key
  from sympy.functions import adjoint
  from sympy.matrices.matrixbase import MatrixBase
  from sympy.matrices.expressions.transpose import transpose
  from sympy.strategies import rm_id, unpack, flatten, sort, condition, exhaust, do_one, glom
  from sympy.matrices.expressions.matexpr import MatrixExpr
  from sympy.matrices.expressions.special import ZeroMatrix, GenericZeroMatrix
  from sympy.matrices.expressions._shape import validate_matadd_integer
  from sympy.utilities.iterables import sift
  from sympy.utilities.exceptions import sympy_deprecation_warning
label_desc: Use image node_id 9 for calling the MatAdd obj's underlying member method code with example usage: obj._eval_trace() and returns: Add